1 //===-- llvm/CodeGen/MachineModuleInfo.h ------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Collect meta information for a module. This information should be in a 11 // neutral form that can be used by different debugging and exception handling 12 // schemes. 13 // 14 // The organization of information is primarily clustered around the source 15 // compile units. The main exception is source line correspondence where 16 // inlining may interleave code from various compile units. 17 // 18 // The following information can be retrieved from the MachineModuleInfo. 19 // 20 // -- Source directories - Directories are uniqued based on their canonical 21 // string and assigned a sequential numeric ID (base 1.) 22 // -- Source files - Files are also uniqued based on their name and directory 23 // ID. A file ID is sequential number (base 1.) 24 // -- Source line correspondence - A vector of file ID, line#, column# triples. 25 // A DEBUG_LOCATION instruction is generated by the DAG Legalizer 26 // corresponding to each entry in the source line list. This allows a debug 27 // emitter to generate labels referenced by debug information tables. 28 // 29 //===----------------------------------------------------------------------===// 30 31 #ifndef LLVM_CODEGEN_MACHINEMODULEINFO_H 32 #define LLVM_CODEGEN_MACHINEMODULEINFO_H 33 34 #include "llvm/ADT/ArrayRef.h" 35 #include "llvm/ADT/DenseMap.h" 36 #include "llvm/ADT/PointerIntPair.h" 37 #include "llvm/MC/MCContext.h" 38 #include "llvm/MC/MCSymbol.h" 39 #include "llvm/Pass.h" 40 #include <memory> 41 #include <utility> 42 #include <vector> 43 44 namespace llvm { 45 46 class BasicBlock; 47 class CallInst; 48 class Function; 49 class MachineFunction; 50 class MMIAddrLabelMap; 51 class Module; 52 class TargetMachine; 53 54 //===----------------------------------------------------------------------===// 55 /// This class can be derived from and used by targets to hold private 56 /// target-specific information for each Module. Objects of type are 57 /// accessed/created with MMI::getInfo and destroyed when the MachineModuleInfo 58 /// is destroyed. 59 /// 60 class MachineModuleInfoImpl { 61 public: 62 using StubValueTy = PointerIntPair<MCSymbol *, 1, bool>; 63 using SymbolListTy = std::vector<std::pair<MCSymbol *, StubValueTy>>; 64 65 virtual ~MachineModuleInfoImpl(); 66 67 protected: 68 /// Return the entries from a DenseMap in a deterministic sorted orer. 69 /// Clears the map. 70 static SymbolListTy getSortedStubs(DenseMap<MCSymbol*, StubValueTy>&); 71 }; 72 73 //===----------------------------------------------------------------------===// 74 /// This class contains meta information specific to a module. Queries can be 75 /// made by different debugging and exception handling schemes and reformated 76 /// for specific use. 77 /// 78 class MachineModuleInfo : public ImmutablePass { 79 const TargetMachine &TM; 80 81 /// This is the MCContext used for the entire code generator. 82 MCContext Context; 83 84 /// This is the LLVM Module being worked on. 85 const Module *TheModule; 86 87 /// This is the object-file-format-specific implementation of 88 /// MachineModuleInfoImpl, which lets targets accumulate whatever info they 89 /// want. 90 MachineModuleInfoImpl *ObjFileMMI; 91 92 /// \name Exception Handling 93 /// \{ 94 95 /// Vector of all personality functions ever seen. Used to emit common EH 96 /// frames. 97 std::vector<const Function *> Personalities; 98 99 /// The current call site index being processed, if any. 0 if none. 100 unsigned CurCallSite; 101 102 /// \} 103 104 /// This map keeps track of which symbol is being used for the specified 105 /// basic block's address of label. 106 MMIAddrLabelMap *AddrLabelSymbols; 107 108 // TODO: Ideally, what we'd like is to have a switch that allows emitting 109 // synchronous (precise at call-sites only) CFA into .eh_frame. However, 110 // even under this switch, we'd like .debug_frame to be precise when using 111 // -g. At this moment, there's no way to specify that some CFI directives 112 // go into .eh_frame only, while others go into .debug_frame only. 113 114 /// True if debugging information is available in this module. 115 bool DbgInfoAvailable; 116 117 /// True if this module calls VarArg function with floating-point arguments. 118 /// This is used to emit an undefined reference to _fltused on Windows 119 /// targets. 120 bool UsesVAFloatArgument; 121 122 /// True if the module calls the __morestack function indirectly, as is 123 /// required under the large code model on x86. This is used to emit 124 /// a definition of a symbol, __morestack_addr, containing the address. See 125 /// comments in lib/Target/X86/X86FrameLowering.cpp for more details. 126 bool UsesMorestackAddr; 127 128 /// True if the module contains split-stack functions. This is used to 129 /// emit .note.GNU-split-stack section as required by the linker for 130 /// special handling split-stack function calling no-split-stack function. 131 bool HasSplitStack; 132 133 /// True if the module contains no-split-stack functions. This is used to 134 /// emit .note.GNU-no-split-stack section when it also contains split-stack 135 /// functions. 136 bool HasNosplitStack; 137 138 /// Maps IR Functions to their corresponding MachineFunctions. 139 DenseMap<const Function*, std::unique_ptr<MachineFunction>> MachineFunctions; 140 /// Next unique number available for a MachineFunction. 141 unsigned NextFnNum = 0; 142 const Function *LastRequest = nullptr; ///< Used for shortcut/cache. 143 MachineFunction *LastResult = nullptr; ///< Used for shortcut/cache. 144 145 public: 146 static char ID; // Pass identification, replacement for typeid 147 148 explicit MachineModuleInfo(const TargetMachine *TM = nullptr); 149 ~MachineModuleInfo() override; 150 151 // Initialization and Finalization 152 bool doInitialization(Module &) override; 153 bool doFinalization(Module &) override; 154 155 const MCContext &getContext() const { return Context; } 156 MCContext &getContext() { return Context; } 157 158 const Module *getModule() const { return TheModule; } 159 160 /// Returns the MachineFunction constructed for the IR function \p F. 161 /// Creates a new MachineFunction if none exists yet. 162 MachineFunction &getOrCreateMachineFunction(const Function &F); 163 164 /// \bried Returns the MachineFunction associated to IR function \p F if there 165 /// is one, otherwise nullptr. 166 MachineFunction *getMachineFunction(const Function &F) const; 167 168 /// Delete the MachineFunction \p MF and reset the link in the IR Function to 169 /// Machine Function map. 170 void deleteMachineFunctionFor(Function &F); 171 172 /// Keep track of various per-function pieces of information for backends 173 /// that would like to do so. 174 template<typename Ty> 175 Ty &getObjFileInfo() { 176 if (ObjFileMMI == nullptr) 177 ObjFileMMI = new Ty(*this); 178 return *static_cast<Ty*>(ObjFileMMI); 179 } 180 181 template<typename Ty> 182 const Ty &getObjFileInfo() const { 183 return const_cast<MachineModuleInfo*>(this)->getObjFileInfo<Ty>(); 184 } 185 186 /// Returns true if valid debug info is present. 187 bool hasDebugInfo() const { return DbgInfoAvailable; } 188 void setDebugInfoAvailability(bool avail) { DbgInfoAvailable = avail; } 189 190 bool usesVAFloatArgument() const { 191 return UsesVAFloatArgument; 192 } 193 194 void setUsesVAFloatArgument(bool b) { 195 UsesVAFloatArgument = b; 196 } 197 198 bool usesMorestackAddr() const { 199 return UsesMorestackAddr; 200 } 201 202 void setUsesMorestackAddr(bool b) { 203 UsesMorestackAddr = b; 204 } 205 206 bool hasSplitStack() const { 207 return HasSplitStack; 208 } 209 210 void setHasSplitStack(bool b) { 211 HasSplitStack = b; 212 } 213 214 bool hasNosplitStack() const { 215 return HasNosplitStack; 216 } 217 218 void setHasNosplitStack(bool b) { 219 HasNosplitStack = b; 220 } 221 222 /// Return the symbol to be used for the specified basic block when its 223 /// address is taken. This cannot be its normal LBB label because the block 224 /// may be accessed outside its containing function. 225 MCSymbol *getAddrLabelSymbol(const BasicBlock *BB) { 226 return getAddrLabelSymbolToEmit(BB).front(); 227 } 228 229 /// Return the symbol to be used for the specified basic block when its 230 /// address is taken. If other blocks were RAUW'd to this one, we may have 231 /// to emit them as well, return the whole set. 232 ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(const BasicBlock *BB); 233 234 /// If the specified function has had any references to address-taken blocks 235 /// generated, but the block got deleted, return the symbol now so we can 236 /// emit it. This prevents emitting a reference to a symbol that has no 237 /// definition. 238 void takeDeletedSymbolsForFunction(const Function *F, 239 std::vector<MCSymbol*> &Result); 240 241 /// \name Exception Handling 242 /// \{ 243 244 /// Set the call site currently being processed. 245 void setCurrentCallSite(unsigned Site) { CurCallSite = Site; } 246 247 /// Get the call site currently being processed, if any. return zero if 248 /// none. 249 unsigned getCurrentCallSite() { return CurCallSite; } 250 251 /// Provide the personality function for the exception information. 252 void addPersonality(const Function *Personality); 253 254 /// Return array of personality functions ever seen. 255 const std::vector<const Function *>& getPersonalities() const { 256 return Personalities; 257 } 258 /// \} 259 }; // End class MachineModuleInfo 260 261 //===- MMI building helpers -----------------------------------------------===// 262 263 /// Determine if any floating-point values are being passed to this variadic 264 /// function, and set the MachineModuleInfo's usesVAFloatArgument flag if so. 265 /// This flag is used to emit an undefined reference to _fltused on Windows, 266 /// which will link in MSVCRT's floating-point support. 267 void computeUsesVAFloatArgument(const CallInst &I, MachineModuleInfo &MMI); 268 269 } // end namespace llvm 270 271 #endif // LLVM_CODEGEN_MACHINEMODULEINFO_H 272
